Left ventricular wall stress and sarcoplasmic reticulum Ca(2+)-ATPase gene expression in renal hypertensive rats: dose-dependent effects of ACE inhibition and AT1-receptor blockade.

BACKGROUND: Cardiac hypertrophy is associated with altered Ca2+ handling and may predispose to the development of LV dysfunction and cardiac failure. At the cellular level, the re-expression of ANF represents a well-established marker of myocyte hypertrophy while the decreased expression of the sarcoplasmatic reticulum (SR) Ca(2+)-ATPase is thought o play a crucial role in the alterations of Ca2+ handling and LV function. We assessed the dose-dependent effect of chronic ACE inhibition or AT1 receptor blockade on cardiac function in relation to the cardiac expression of the SR Ca(2+)-ATPase and ANF. METHODS AND RESULTS: Renal hypertensive rats (2K-1C) were treated for 12 weeks with three different doses of the ACE inhibitor benazepril, the AT1-receptor antagonist valsartan (each drug 0.3, 3, and 10 mg/kg per day i.p.) or placebo. LV dimensions, hypertrophy and wall stress were determined in vivo by magnetic resonance imaging and the gene expressions of ANF and SR Ca(2+)-ATPase were quantified by Northern blot. Low doses of both drugs did not affect blood pressure, hypertrophy, systolic wall stress and the ANF and SR Ca(2+)-ATPase gene expression. High doses of each drug reduced systolic blood pressure, wall stress, and LV hypertrophy to a similar extent and to values comparable to normotensive, age-matched rats. In addition, high dose treatment reduced LV end-systolic and end-diastolic volume as compared to untreated 2K-1C animals and normalized the mRNA levels of both ANF and SR Ca(2+)-ATPase (as compared to normotensive animals). CONCLUSIONS: We conclude that in this model, high doses of ACE inhibition and AT1-receptor blockade are necessary to normalize systolic blood pressure, LV hypertrophy and systolic LV wall stress which, in turn, is associated with restoration of a normal cardiac phenotype with respect to SR Ca(2+)-ATPase and ANF and normalization of cardiac function.

Prolonged angiotensin II antagonism in spontaneously hypertensive rats. Hemodynamic and biochemical consequences.

The present study examines the effects of prolonged angiotensin II antagonism in spontaneously hypertensive rats by using an angiotensin II receptor antagonist (DuP 753) that is devoid of agonistic properties and selective for the subtype 1 of the angiotensin II (AT1) receptor. The antihypertensive effects of DuP 753 and its effects on circulating parameters of the renin-angiotensin system were compared with those of a converting enzyme inhibitor (benazeprilat). To minimize any influence of differences in the pharmacokinetic properties of the two blockers, administration was by continuous intravenous infusion. The experiments were performed in conscious, freely moving rats with continuous 24-hour monitoring of blood pressure. DuP 753 (10 or 30 mg/kg/day) lowered mean arterial pressure to the same extent as benazeprilat (3 or 10 mg/kg/day) during a 48-hour period. The antihypertensive effect was sustained when the treatment was extended to 7 days (DuP 753, 10 mg/kg/day; benazeprilat, 3 mg/kg/day). Neither of the compounds affected the baseline or diurnal rhythm of heart rate. Plasma concentrations of renin and angiotensin II were increased sevenfold and 10-fold, respectively, in the rats treated with DuP 753. In rats treated with benazeprilat, plasma renin concentration increased threefold, whereas angiotensin II was unchanged. Heart weights were significantly reduced to a similar extent by DuP 753 and benazeprilat. Both compounds also induced a smaller but significant decrease in blood pressure in Wistar-Kyoto rats. Our results indicate that the antihypertensive effects of converting enzyme inhibitors in spontaneously hypertensive rats are mainly due to the blockade of the renin-angiotensin system. In this rat model, angiotensin II appears to play an important role in the maintenance of hypertension that is mediated via the AT1 receptor.

Biochemical effects of prolonged renin inhibition in marmosets.

The renin inhibitor CGP 29,287 was administered continuously for 7 days (30 mg/kg per day, intraperitoneally, via osmotic minipumps) to normotensive marmosets fed a low-salt diet. As a control, another group of marmosets was given vehicle only. After 7 days of treatment, the mean arterial blood pressure of the CGP 29,287-treated marmosets was significantly lowered by about 23 mmHg. Plasma immunoreactive total and active renin were increased 10- and sevenfold, respectively, whereas plasma renin activity (PRA) was reduced by 95%. Plasma angiotensin II (Ang II) and aldosterone were also reduced (by 97 and 85%, respectively). Serum angiotensin converting enzyme activity was unchanged and there were no differences in plasma concentrations of electrolytes, urea or creatinine between CGP 29,287-treated and control marmosets. These results indicate that although renin release is markedly stimulated after continuous administration of a renin inhibitor for 7 days, the formation of Ang II and aldosterone, the active hormones of the renin-angiotensin system, is substantially reduced.

Mechanism of leptin removal from the circulation by the kidney.

This study was performed to test the hypothesis that the kidneys play a primary role in the clearance of endogenous leptin from the circulation. Lean male Sprague-Dawley rats were anesthetized and subjected to various surgical manipulations of the kidneys. Sixty minutes after surgery arterial blood samples were taken at 1-h intervals for up to 8 h. Plasma leptin levels were determined by radioimmunoassay. Bilateral nephrectomy induced a rapid increase in plasma leptin concentrations above control values, indicating that the kidneys are important for the elimination of leptin from the circulation. Leptin was not metabolized across the renal circulation and was extracted intact by the kidney. Simultaneous measurement of renal plasma flow established renal leptin extraction at approximately 6.5 ng/min for both kidneys. Compared with the quantities extracted from the plasma, leptin was only present in the urine in small quantities, indicating extensive metabolic degradation in the renal tubules. High plasma leptin levels were not maintained after binephrectomy indicating that pathways other than the kidneys are also responsible for leptin clearance. Seven hours after bilateral ureteral ligation, a procedure which lowers glomerular filtration, plasma leptin levels were slightly elevated. The renal extraction of leptin did not change over a wide range of plasma leptin concentrations suggesting that renal leptin extraction is a high capacity, non-saturable process most probably glomerular filtration. Endogenous leptin is rapidly cleared from the circulation by glomerular filtration followed by metabolic degradation in the renal tubules.

Ki-67 antigen expression and growth pattern of basal cell carcinomas.

The expression and location of the Ki-67 antigen was investigated in 62 basal cell carcinomas (BCC) using immunostaining techniques (PAP and APAAP) on cryostat sections. The tumor samples were classified into three groups according to microarchitecture (nodular, superficial or fibrosing). The Ki-67 growth fraction displayed great variation between tumors belonging to the same group (nodular type, 7-67%; superficial type, 18-49%; fibrosing type 4-33%). In nodular and superficial BCC formations Ki-67 reactivity was confined either to the nuclei of three to five rows of peripheral cells, or Ki-67-positive nuclei were scattered in the central as well as in the peripheral parts of the tumor strands. The staining patterns varied in an individual tumor. Areas with a high Ki-67 labelling index often occurred adjacent to rather quiescent strands, suggesting that an individual tumor is not in a uniform state of proliferation. So far there are no experimental findings on the regulation of proliferative activity in BCCs. In view of the fact that BCCs are rather slow-growing tumors, the large Ki-67 growth fractions indicate a prolonged duration of the cell cycle or a considerable continuous loss of cells. As the microarchitecture of BCCs is much more complex than would be expected from the location of their Ki-67-positive cells, the growth pattern is probably determined to a high degree by the adjacent connective connective tissue (physical properties and texture of collagen and elastic fibres, enzyme activity of fibroblasts).

Inhibition of renin-like activity in marmoset tissues by the renin inhibitor CGP 29 287.

This study investigated the contribution of tissue renin-like activity to the acute hypotensive response induced by the potent and specific inhibitor of primate renin, CGP 29 287. Furosemide-pretreated marmosets (5mg/kg, i.m.) were killed 30 min after bolus injection of CGP 29 287 (1 mg/kg, i.v., n = 4). At this time, plasma renin activity is completely inhibited and the hypotensive response is maximal. Control marmosets received vehicle (0.9% saline, 1 ml/kg, i.v.). Renin-like activity was measured by the rate of angiotensin I (ANG I) formation after incubation of tissue homogenates with sheep angiotensinogen at pH 6.0 and 7.4. Activity was detected in the brain, heart, aorta and kidney of CGP 29 287-treated and control marmosets, and there were no significant differences in the values between the two groups. Addition of CGP 29 287 (5 X 10(-6) mol/l) to tissue homogenates in vitro inhibited ANG I formation (greater than 80%). These results indicate that CGP 29 287 is an inhibitor of tissue renin-like activity in vitro, but does not inhibit activity in these tissues after acute administration in vivo. Thus, the acute hypotensive response to CGP 29 287 appears to be due to inhibition of circulating renin only.

Haemodynamic effects of acute and chronic renin inhibition in marmosets.

We have developed marmoset models for the in vivo evaluation of primate-specific inhibitors of human renin. After acute intravenous administration to normotensive sodium-depleted marmosets, renin inhibitors of different structural types induced a maximum hypotensive response of a magnitude similar to that induced after angiotensin converting enzyme (ACE) inhibition. The response was prevented by pretreatment with an ACE inhibitor. A close relationship between the inhibition of plasma renin activity (PRA) and the fall in blood pressure was observed with most of the inhibitors. CGP 29,287, a synthetic renin inhibitor, and R-3-36-16, a monoclonal antibody, both induced a selective increase in renal blood flow similar to that induced by an ACE inhibitor. A sustained reduction in blood pressure was observed during continuous administration of CGP 29,287 or R-3-36-16 over 14 days, despite an increase in immunoreactive renin and an apparent recovery of PRA. A similar blood pressure fall and an increase in plasma renin was observed during continuous administration of an ACE inhibitor. The renin inhibitor CGP 29,287 also lowered blood pressure after acute administration to hypertensive marmosets with normal PRA. Our studies demonstrate that renin inhibitors have similar haemodynamic effects to ACE inhibitors, and indicate that they may have a similar antihypertensive efficacy.

Contribution of vascular and tubular effects of arginine-vasopressin to the development of deoxycorticosterone acetate (DOCA)-salt hypertension in rats.

The role of arginine-vasopressin (AVP) in the pathogenesis of deoxycorticosterone acetate (DOCA) salt hypertension in rats was studied with AVP receptor antagonists for its tubular (V2) and/or vascular (V1) actions. When chronic (six weeks) infusion of the antagonists was started concomitantly with DOCA-salt treatment the development of hypertension was attenuated by the V1-antagonist and prevented by the V1V2-antagonist. However, the V1V2-antagonist induced severe and persistent hypernatraemia in all rats. When chronic (two weeks) infusion of the antagonists was started in rats with established hypertension after five weeks of DOCA-salt treatment blood pressure was not influenced by the V1-antagonist. The rats which received the V1V2-antagonist died from hypernatraemia within four days. These results suggest that in DOCA-salt treated rats AVP is essential for the prevention of severe and life-threatening hypernatraemia. AVP appears to contribute significantly to the development of this form of hypertension through both its vascular and tubular effects.

[Hailey-Hailey pemphigus--one only sees what one recognizes]. / Pemphigus Hailey-Hailey--man sieht nur was man kennt.

A diagnosis of Pemphigus Hailey-Hailey was made by histopathology after more than 20 years of suffering and medical treatment. The lesion had almost exclusively affected the vulvar region of a 44-year-old woman. A case like this confronts the gynecologists with the necessity of including a rare disease into particular consideration and investigation.

[Solitary basalioma in a 10-year-old boy]. / Solitäres Basaliom eines 10jährigen Jungen.

It is rare for solitary basal cell cancer not to be associated with the naevoid basal cell carcinoma syndrome (NBCCS), xeroderma pigmentosum, an organoid nevus or X-ray therapy in children (to date 86 cases have been documented in the literature. Aetiologically, the tumours might be a forme fruste of the NBCCS or they might follow a somatic point mutation of keratinocytes. Up to now, data on the repair mechanism following UV-induced DNA damage are not available in these patients. We report on a 10-year-old boy with a solitary nodular basal cell cancer in the right malar region. Neither the patient's history nor the clinical findings suggested a genetic disposition to development of the tumour.

Contact stomatitis due to palladium and platinum in dental alloys.

We report a patient with contact stomatitis due to combined sensitization to palladium and platinum. Patch testing showed strong and persistent allergic patch test reactions to palladium chloride (1% pet.), ammonium tetrachloroplatinate (0.25% pet.), and a palladium metal plate. A platinum metal plate showed a weaker reaction. Histological examination of a biopsy from the test site of palladium chloride (1% pet.) at D3 showed both eczematous and lichenoid changes.

Differentiation of granuloma cells (epithelioid cells and multinucleated giant cells): a morphometric analysis. Investigations using the model of experimental autoimmune (anti-TBM) tubulo-interstitial nephritis.

Morphometric analysis disclosed distinct differences between blood monocytes, tissue monocytes (i.e. immature macrophages), epithelioid cells and multinucleated giant cells as well as phagocytic macrophages (i.e. mature macrophages) in the granuloma model of autoimmune (anti-TBM) tubulo-interstitial nephritis. The numerical density of lysosomes decreased slightly in tissue monocytes compared with blood monocytes but showed a pronounced increase during the formation of epithelioid cells. The lysosomal compartments of epithelioid cells and multinucleated giant cells resembled each other very closely, but the giant cells obviously produced additional lysosomes of small diameter (80-120 nm). Phagocytic macrophages displayed a total numerical density of lysosomes similar to that of tissue monocytes but the mean diameter of the lysosomes was markedly greater. Thus the volume density of lysosomes was highest in phagocytic macrophages. The blood monocytes exhibited the smallest lysosomal compartment. In tissue monocytes, epithelioid cells, and multinucleated giant cells the volume densities of the lysosomes were greater than in blood monocytes and remained relatively constant because the increase in numerical density was counterbalanced by a decrease in mean granule diameter. We found only minor differences in mitochondrial volume densities among the five cell populations. The shape of the mitochondria, however, changed steadily from short rotational ellipsoids in the blood monocytes to rather elongated and slender bodies in the multinucleated giant cells. The results suggest that epithelioid cells and multinucleated giant cells are active cells which may contribute by their specific performances, to the immunologic microenvironment of the granuloma.

Freeze-fracture features of epithelioid cells, multinucleated giant cells, and phagocytic macrophages. Investigations using the model of experimental autoimmune (anti-TBM) tubulo-interstitial nephritis.

The freeze-fracture morphology of epithelioid cells, multinucleated giant cells (Langhans' type), and phagocytic macrophages was investigated. The intensely folded and interdigitating surface membranes of epithelioid cells and multinucleated giant cells displayed no specialized areas of cell contact. The size of the intramembranous particles (IMP) and the fact that the area density of IMPs was higher in the cytoplasmic (P) faces than in the external (E) faces of the cell membranes agreed with observations in other eukaryotic cells. The area densities of the IMPs suggest lower transport rates of molecules across the cell membranes of granuloma cells than of certain epithelial cells. Small pits were detected in the surface membranes of the granuloma cells but an extrusion of granules was not observed. The cytoplasmic granules displayed very different sizes and shapes ranging from spherical to rod-shaped. The latter type of granules (probably primary lysosomes) dominated in multinucleated giant cells. The granule membranes were studded with IMPs whose area densities increased with the granule size. Multilamellar bodies with smooth (lipid) fracture faces were found only in phagocytic macrophages. The nuclear pores of the granuloma cells were distributed over the entire surfaces of the nuclei and displayed moderate clustering. The values of the area densities of the nuclear pores were in keeping with the values observed in mammalian and human epithelial or mesenchymal cells, indicating similar exchange rates of molecules between the nucleoplasm and the cytoplasm in these different cell types. In a single phagocytic macrophage the E-face of the inner membrane of the nuclear envelope displayed a network of fine filaments whose nature is at present unknown.

[Verruciform palmoplantar keratoderma as a characteristic marker of hidrotic ectodermal dysplasia of the Clouston type]. / Warzenförmige palmoplantare Keratodermie als charakteristisches Merkmal der hidrotischen ektodermalen Dysplasie vom Typ Clouston.

We report on a 23-year-old man with hidrotic ectodermal dysplasia of the Clouston type showing a severe expression of his gene defect. As a prominent feature of this case, we describe the presence of verruciform keratoderma of hands and feet, and we visualize these skin changes by means of a new imprinting technique.

Expression of proliferation-associated proteins (proliferating cell nuclear antigen and Ki-67 antigen) in Bowen's disease.

Bowen's disease and invasive squamous cell carcinoma arising in Bowen's disease (Bowen's carcinoma) were investigated immunohistochemically with regard to their expression of proliferating cell nuclear antigen (PCNA) and the Ki-67 antigen. Both proliferation-associated proteins were found in all layers of the tumours, and were present in nuclei of any size and shape. The nucleoli lacked PCNA immunoreactivity, but they expressed the Ki-67 antigen. The PCNA labelling index was 36.9 +/- 12.6% in Bowen's disease (n = 16), and 40.7 +/- 11.0% in Bowen's carcinoma (n = 3). The Ki-67 antigen labelling index was 43.6 +/- 16.7% in Bowen's disease (n = 16), and 51.7 +/- 11.6% in Bowen's carcinoma (n = 3). Dyskeratotic cells were positive for PCNA and the Ki-67 antigen, suggesting that these cells are not in a post-mitotic state. We conclude that in dyskeratotic cells of Bowen's disease the cell cycle is interrupted by nuclear disorganization.

Fixation requirements for the immunohistochemical reactivity of PCNA antibody PC10 on cryostat sections.

In contrast to that in paraffin-embedded tissue, the reactivity of monoclonal PCNA antibody PC10 on cryostat sections requires a special fixation procedure as the target epitope is seemingly not accessible to its antibody. A panel of 18 fixation protocols was investigated. Chilled methanol or acetone, or PLP (paraformaldehyde-lysine-periodate) was found to be unsuitable for skin preparations. A two-step fixation protocol was developed for normal skin and basal cell carcinomas. They were fixed first in 3.4% buffered formaldehyde, followed by fixation in 2:1 v/v ethanol-acetic acid. Following this fixation regime, cryostat sections displayed the same PCNA/PC10 labelling pattern as paraffin sections of formalin-fixed tissue.

[Sarcoidal allergic contact dermatitis due to palladium following ear piercing]. / Sarkoidale allergische Kontaktdermatitis auf Palladium nach Ohrpiercing.

Granulomatous tissue reactions due to jewelry made of gold, silver, nickel and palladium are rare but nevertheless have been known for a long time. A female patient developed nodular infiltrates after having been pierced with ear stickers containing palladium. A contact allergic reaction could be demonstrated as the underlying cause by inducing similar histological changes following patch testing with palladium.

[Cutaneous manifestation of cysticercosis]. / Kutane Manifestation der Zystizerkose.

Cysticercosis, an infection with the larva of Taenia solium, is caused by the accidental ingestion of the parasite's eggs. In many countries of the Third World, cysticercosis, and especially neurocysticercosis, is a widespread problem. A patient from Northern Malawi presented not only with cysticercosis but also with BT leprosy and pityriasis versicolor. Dermatologists should be familiar with the clinical picture of cysticercosis in order to make an early diagnosis in patients from at-risk areas.

Leptin is cleared from the circulation primarily by the kidney.

OBJECTIVE: This study was performed to determine the pharmakocinetics of recombinant leptin in lean rats and to test the hypothesis that the kidneys play an important role in the clearance of leptin from the circulation. DESIGN: 126I-leptin was administered by bolus intravenous injection. Blood samples were taken at various time points ranging from 1-180 min after administration and assayed for leptin. Pharmacokinetic parameters were determined in normal animals and after either bilateral nephrectomy or bilateral ureteral ligation. RESULTS: Leptin was eliminated from the circulation following a three compartment model. The importance of the kidneys to the systemic clearance of leptin was studied by administrating leptin to binephrectomized rats. The systemic clearance of leptin in anephric rats was only 19% of that calculated for control animals. In order to assess the role of glomerular filtration, both ureters were ligated 5 h before leptin administration. Ureteral ligation reduced the systemic clearance of leptin by 30%. CONCLUSION: These findings demonstrate that the short half life of leptin in the circulation is mainly determined by efficient renal clearance which is mediated in part by glomerular filtration.

Rapid and unbiased estimation of the volume of cutaneous malignant melanoma using Cavalieri's principle.

The Cavalieri volume estimator has been employed to determine the macroscopic tumor volume of 34 cutaneous malignant melanomas. With this rapid and unbiased method using histological specimens from slabs of known thickness, tumor volumes between 3.9 mm3 and 841.5 mm3 were found. The coefficient of error (CE) for tumor volumes ranged between 0.028 and 0.141, with a combined group CE of 0.043. There was a remarkably good correlation between tumor volume and maximal vertical tumor thickness estimated according to Breslow, with a correlation coefficient of r = 0.86 for all tumors, and of r = 0.82, if the one extremely big tumor is omitted. Both inter- and intraobserver variability was very low, with only approximately 1-2% difference. Thus, the method described allows for the reproducible, rapid, and unbiased estimation of tumor volume independent of the shape of the tumor.